Modern Musclecar

I have several nice expensive valve spring compressors and the one I use the most was the cheapest. Just a simple bolt to the rocker perch and use leverage to compress style

philpacs

I have put over 15K and about 45 hard track days on my replacement engine. At that time I did the most standard fix of Bronze guides, SS exhaust valve(apparently anchors according to the forum), springs and at that time milled, port/polish heads, kooks headers and torquer cam. No issues, knock on wood.

I can tell you I lost much respect for GM to admit a machining error but not cover at least testing to see if guides are out of spec or whatever method they suggest to see if your car is one of the affected. That's it GM admit a problem that could cause a major catastrophe and do nothing about it. Company integrity also shown when they got caught of another recent issue with another car and instead of doing the right thing and doing a recall they paid a fine. Maybe all manufacturers would do that and I expect too much but doing the right thing would earn more customers for life.

Dan_the_C5_Man

The second one in the pictures above is what I would recommend. I ended up going cheaper (and availability / timing was an issue for me as well), and although the one I bought does get the job done, I wished I would have sprung for the second one pictured above.

ipmtim

Any info on the 2nd one would be great. I can't read the name on it from the pic
Thanks,
Tim

Dan_the_C5_Man

It's this one (do a search, not sure if I can post the links to Summit or Jegs, but they both sell it). LSM-SC-167

Michael_D

I learned a long time ago the wisdom of the phrase: "Trust, but verify".

With regards to cylinder heads, no matter where they came from, new/refurbished/modified/etc..... I break them down and perform a complete inspection. Clarence’s, stem finish, valve seals, valve run-out, seat run-out, spring load/rate, spring install height….

I trusted, but did not verify a brand new set of AFR’s on a SBC once. Third mellow, low rpm pull on the dyno to seat the rings and had three valves stick and bump ugglies with the pistons. Clearances were way too tight.

So, I think it would be very unwise to not do the same with new GM heads. I gave this same advice to someone on this forum about a year ago, and fortunately, he actually took this advice and found several seats out of spec.

JoesC5

I think that most on this forum have forgotten(or never knew) that the original MarkV 427 had stainless intakes that were 2.190" dia and the stainless exhaust valves were 1.88" dia.

Those MarkV engines were spun to 7,000(6500 redline on tachometer) all the time.

The stainless valves on the small block high performance 327cu in engine were 2.02' dia intakes and 1.62" dia exhausts. Even with a 6,500 redline on the dash's tachometer, they were spun much higher that that.

They were quite a bit heavier than the Ti intakes on the LS7 at 2.20" dia and the hollow stem stainless exhaust at 1.61" dia.



Back in 1961 I had 1.845" dia intakes(stainless) in my 301 cu in SBC and ran it to 8,500 RPM. I never snapped a valve head off.

I'm not concerned that my SS exhaust valves are of solid stem construction in my LS7's heads.

Les

I actually had that done on the AFRs that are on my avatar car.

Michael, I'm thinking about getting a spring compressor so that I can do my own wiggle test. Bearing in mind that I'm not a pro and don't need the most expensive tool but one that gets it done properly, what would you recommend?

reasonable suspicion

Why is there not anyone who not only has common sense, but who also cares about the customer such as yourself in the gm hierarchy?

philpacs

Interesting information. Good to know, Thanks

wjnjr

SC 167




Here's the manufacturer's web site: http://www.lsmproducts.com/lsm_produ..._removal_tools

ipmtim

Already looked it up and found it.
Just trying to decide. Do I keep the car (which is the most fun car I've ever owned) and fight this valve train forever in which I'll invest the $200+ for the tool,
or dump the car and buy something I can enjoy, although not as much and not worry about the ticking time bomb every time I hit the start button
Tim

Les

I'm considering getting one- would you mind sharing specifics on the simple one you're talking about? This would be to use with the heads still on the engine.

Michael_D

I have the Comp and it works - OK. If I were to buy one today, it would be the LSM model. This is for installed heads. For removed, I have a large clamp style with universal jaws.

MyLS1Hauls

I think you meant Mark IV, as those were the 427s.

I hear what you are saying, but there are some other things that aren't being considered. RPM and valve weight aren't the only variables. Cam profile, rocker arm ratio and mass, lifter mass, valve spring diameter/pressure are equally important.

The most popular 427s had gross valve lift under .550" (have to subtract valve lash from this number), and it was a solid flat tappet. They're usually faster on and off the seat than a hyd roller, but not as aggressive overall. The acceleration rates that the LS7 valves see are much greater than the old motors. This changes the requirements of the valve and spring. Now, I'm not saying you can't use a solid valve in the LS7. I'm just pointing out the differences that often go unmentioned.

chadyellowz

I did an 11 crate engine install for a friend, put 1k miles on the heads pulled sent to a well known vendor for bronze guide exhaust valve ect. after 10k miles heads were out of spec here is the vid of those heads, and i'll add a vid of the tool i use to check valve guides on the car

Vito.A

Interesting comparison with the original 427 Big BlockChevys. The L88 was the king with 430 hp (most sanctioning organizations rated it at 600hp). It had solid lifters with 2.19" and 1.88" stainless valves with a redline of 6500 and a valve train limit speed of 7200, but the springs were much larger than our LS7. The rocker ratio was 1.7-1 and the entire valve train was heavy duty (7/16" pushrods). I used to buy brand new L88 427 short blocks for less than $500 back in the early 70’s.

The new replacement LS7 heads come from GM without valves or springs. Most of these are taken to a machine shop for assembly. Any competent machine shop does a touch up on the seats. This usually involves a machine that centers on the valve guide. This process will correct most of the incorrect machining done at Linamar (most of us have not addressed the incorrect rocker stud placement).

Minkster

Replacement heads I got under warranty last year were complete. Came out of the GM Performance Catalog.

Hib Halverson

The guides in the warranty replacement heads were not the problem.

The replacement heads had a number of valve seats with excessive runout. Rather than wait for a second set of replacement heads, because time was of the essence due to the car in question being the Lead Car for the 2014 National Corvette Caravan out of California 10 days later, I ordered my cylinder head service to repair them. Because of the circumstances my repair of the replacement heads was covered under warranty.

It is true that Linimar was not holding the required tolerance for seat runout on a consistent basis, however, it is a distortion of fact to say:

Les

Thanks. I assume it's this one, which is what Chad shows in his video.
http://www.summitracing.com/parts/cca-5462